A matrix model for a quantum hall droplet with manifest particle-hole symmetry

We find that a gauged matrix model of rectangular fermionic matrices (a matrix version of the fermion harmonic oscillator) realizes a quantum hall droplet with manifest particle-hole symmetry. The droplet consists of free fermions on the topology of a sphere. It is also possible to deform the Hamiltonian by double trace operators, and we argue that this device can produce two body potentials which might lead the system to realize a fractional quantum hall state on the sphere. We also argue that a single gauged fermionic quantum mechanics of hermitian matrices realizes a droplet with an edge that has $c=1/2$ CFT on it.Comment: 25 pages, uses JHEP format, young.sty (included). v2: Updated references, typos correcte

The Minimal Quiver Standard Model

This paper discusses the minimal quiver gauge theory embedding of the standard model that could arise from brane world type string theory constructions. It is based on the low energy effective field theory of D-branes in the perturbative regime. The model differs from the standard model by the addition of one extra massive gauge boson, and contains only one additional parameter to the standard model: the mass of this new particle. The coupling of this new particle to the standard model is uniquely determined by input from the standard model and consistency conditions of perturbative string theory. We also study some aspects of the phenomenology of this model and bounds on its possible observation at the Large Hadron Collider.Comment: 4 pages, 1 figure. v2: minor correction, added reference. v3: added references. Typos fixed. Improved discussio

Strings on conifolds from strong coupling dynamics: quantitative results

Three quantitative features of string theory on AdS_5 x X_5, for any (quasi)regular Sasaki-Einstein X_5, are recovered exactly from an expansion of field theory at strong coupling around configurations in the moduli space of vacua. These configurations can be thought of as a generalized matrix model of (local) commuting matrices. First, we reproduce the spectrum of scalar Kaluza-Klein modes on X_5. Secondly, we recover the precise spectrum of BMN string states, including a nontrivial dependence on the volume of X_5. Finally, we show how the radial direction in global AdS_5 emerges universally in these theories by exhibiting states dual to AdS giant gravitons.Comment: 1+28 pages. 1 figur

Aspects of emergent geometry in the AdS/CFT context

We study aspects of emergent geometry for the case of orbifold superconformal field theories in four dimensions, where the orbifolds are abelian within the AdS/CFT proposal. In particular, we show that the realization of emergent geometry starting from the N=4 SYM theory in terms of a gas of particles in the moduli space of vacua of a single D3 brane in flat space gets generalized to a gas of particles on the moduli space of the corresponding orbifold conformal field theory (a gas of D3 branes on the orbifold space). Our main purpose is to show that this can be analyzed using the same techniques as in the N=4 SYM case by using the method of images, including the measure effects associated to the volume of the gauge orbit of the configurations. This measure effect gives an effective repulsion between the particles that makes them condense into a non-trivial vacuum configuration, and it is exactly these configurations that lead to the geometry of X in the AdS x X dual field theoryComment: 24 page

Giant magnon bound states from strongly coupled N=4 SYM

We calculate in a very simple way the spectrum of giant magnon bound states at strong coupling in N=4 SYM, by utilizing the description of the field theory vacuum in terms of a condensate of eigenvalues of commuting matrices. We further show that these calculations can be understood in terms of the central charge extension that permits the calculation of BPS masses in the Coulomb branch of N=4 SYM. This paper shows further evidence that the strong coupling expansion of the maximally supersymmetric Yang-Mills theory in four dimensions can be done systematically from first principles, without the assumption of integrability.Comment: 19 pages, uses revte

Multi-matrix models and emergent geometry

Encouraged by the AdS/CFT correspondence, we study emergent local geometry in large N multi-matrix models from the perspective of a strong coupling expansion. By considering various solvable interacting models we show how the emergence or non-emergence of local geometry at strong coupling is captured by observables that effectively measure the mass of off-diagonal excitations about a semiclassical eigenvalue background. We find emergent geometry at strong coupling in models where a mass term regulates an infrared divergence. We also show that our notion of emergent geometry can be usefully applied to fuzzy spheres. Although most of our results are analytic, we have found numerical input valuable in guiding and checking our results.Comment: 1+34 pages, 4 figures. References adde

Quantizing Open Spin Chains with Variable Length: an example from Giant Gravitons

We study an XXX open spin chain with variable number of sites, where the variability is introduced only at the boundaries. This model arises naturally in the study of Giant Gravitons in the AdS/CFT correspondence. We show how to quantize the spin chain by mapping its states to a bosonic lattice of finite length with sources and sinks of particles at the boundaries. Using coherent states, we show how the Hamiltonian for the bosonic lattice gives the correct description of semiclassical open strings ending on Giant Gravitons.Comment: 4 pages. v2: updated reference

Evidence for fast thermalization in the plane-wave matrix model

We perform a numerical simulation of the classical evolution of the plane-wave matrix model with semiclassical initial conditions. Some of these initial conditions thermalize and are dual to a black hole forming from the collision of D-branes in the plane wave geometry. In particular, we consider a large fuzzy sphere (a D2-brane) plus a single eigenvalue (a D0-particle) going exactly through the center of the fuzzy sphere and aimed to intersect it. Including quantum fluctuations of the off-diagonal modes in the initial conditions, with sufficient kinetic energy the configuration collapses to a small size. We also find evidence for fast thermalization: rapidly decaying autocorrelation functions at late times with respect to the natural time scale of the system.Comment: 5 pages, 5 figures, revtex4 format; v2: minor typos fixed; v3: 8 pages, 9 figures, minor changes, includes a supplement as appeared on PR

Strings on conifolds from strong coupling dynamics, part I

A method to solve various aspects of the strong coupling expansion of the superconformal field theory duals of AdS_5 x X geometries from first principles is proposed. The main idea is that at strong coupling the configurations that dominate the low energy dynamics of the field theory compactified on a three sphere are given by certain non-trivial semi-classical configurations in the moduli space of vacua. We show that this approach is self-consistent and permits one to express most of the dynamics in terms of an effective N=4 SYM dynamics. This has the advantage that some degrees of freedom that move the configurations away from moduli space can be treated perturbatively, unifying the essential low energy dynamics of all of these theories. We show that with this formalism one can compute the energies of strings in the BMN limit in the Klebanov-Witten theory from field theory considerations, matching the functional form of results found using AdS geometry. This paper also presents various other technical results for the semiclassical treatment of superconformal field theories.Comment: 52 pages, JHEP3 styl